My tomatoes shot up last spring, I believe partly due to my mixture of manure, compost, and organic fertilizer. I held my breath waiting for the first green fruits to catch my eye.
Finally, I saw them! But soon I noticed that at the bottom of my tall tomato plants, the leaves began to turn yellow, and some of them had brown spots.
At that time we had received an above-average amount of rainfall, and after additional periods of rainfall, the problem seemed to worsen.
Why did my tomato plants have yellow leaves at the bottom?
The answer, I learned, was early blight. Early blight is a fungus that occurs and spreads in wet and humid conditions. Since the fungus originates from the soil-level, early blight begins on leaves toward the bottom of the plant. When rain splashes on the ground, the fungal spores attach to the low-lying leaves.
What to do?
Not wanting to use fungicide mainly because I can be lazy/cheap and didn’t want to go buy it, I decided I’d try another way.
I simply cut off the yellowing stems. Not only were the lower leaves shaded most of the time, I also knew that by cutting these leaves off, I could inhibit the pathway for the fungus to reach the rest of the plant.
Though I still had a few issues with the yellowing leaves that season, for the most part (thanks partly to a dry spell and heat) the plants rebounded and produced healthy red tomatoes.
Do you have early blight on your tomatoes? Here are my recommendations:
- Clip stems as soon as you begin to notice the yellowing of the lower leaves with brown spots. If you let them stay on the plant, the fungus will travel up the plant. Plus, by catching it early, you won’t have to take away too many leaves and stems.
- Use clippers instead of your hands. Some stems are so far gone they’ll come off easily, but most of them won’t. By tugging at them, you run the risk of damaging the plant and breaking off healthy stems. (However, if you’re like me and you find yourself without your clippers on occasion, tugging from the bottom to the top helps the stem snap better than a top-to-bottom motion.)
- Continue checking for yellowing over the next few weeks, especially after a rain.
- Remove (or tie up) any lower stems touching the ground, even if they are healthy. They run the risk of being affected eventually.
Important things to know about the yellow leaves on the bottom of your tomato plant:
The yellow leaves will not return to green. Once a leaf is affected, there really isn’t hope for that leaf and even that stem. Cut it off as quickly as possible to stop the spread up the plant. Most likely, your upper leaves — which receive the light anyway — are still healthy if you caught it early enough.
One More Suggestion
If you continually battle early blight, I share a quick tip in this video that I’ve found to help me in my garden:
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